Not applicable.
1. Field of the Invention
The present invention generally relates to seismic operations. More particularly, the invention relates to seismic operations using satellites to provide communication between the field of operations and the office environment. Still more particularly, the invention relates to an integrated satellite-based seismic information system, facilitating efficient management of resources and assets in the field.
2. Background of the Invention
The field of seismology focuses on the use of artificially generated elastic waves to locate subsurface structures which may contain mineral deposits such as hydrocarbons, ores, water, and geothermal reservoirs. Seismology also is used for archaeological purposes and to obtain geological information for engineering. Exploration seismology provides data that, when used in conjunction with other available geophysical, borehole, and geological data, can provide information about the structure and distribution of rock types and their contents.
Most oil and gas companies rely on the interpretation of seismic data for selecting the sites in which to invest in drilling exploratory and production oil and gas wells. Despite the fact that seismic data is used to map geological structures rather than finding petroleum directly, the gathering of seismic data has become a vital part of selecting the site of an exploratory and/or development well. Experience has shown that the use of seismic data greatly improves the likelihood of a successful venture.
The process of designing, planning, taking seismic measurements, and processing the data generally is referred to as a xe2x80x9cseismic project.xe2x80x9d Although the scale of seismic projects vary depending on the depth of the subsurface structures, size of the area to be surveyed, and other factors, most seismic projects use a common set of equipment. A xe2x80x9csourcexe2x80x9d device creates the energy that propagates into the earth. xe2x80x9cReceiversxe2x80x9d detect the energy after it reflects off subsurface interfaces between rock formations. The time between emitting the impulse from the source and detecting the reflected impulse by a receiver is used to determine the distance to the subsurface structure under investigation. At least several different energy sources have been used at times, but most large scale land-based projects (seismic projects can also be performed at sea) use either high amplitude explosives or lower amplitude vibrators as the source.
Explosives produce high-energy, short time duration impulses. The explosive source and the associated data acquisition and processing system are relatively simple. Explosive charges usually are placed into holes drilled in the ground by drilling trucks, portable drills and personnel, and subsequently detonated.
Seismic projects alternatively may use low magnitude, vibratory energy. Rather than imparting a high magnitude pressure pulse into the earth in a very short time period as with explosive charges, vibratory sources emit lower amplitude pressure waves over a longer time period typically between 5 and 7 seconds, but longer time periods are also possible. A total interval of 5 to 32 seconds is possible. Further, the frequency of the vibrating source varies from a low of about 5 to 10 Hz to a high of 100 to 150 Hz, although the specific low and high frequencies differ from system to system. The frequency of the source may vary linearly with respect to time or non-linearly. The frequency variations are commonly called a xe2x80x9cfrequency sweep.xe2x80x9d The frequency sweep thus typically is between 5 and 150 Hz and on average 12 seconds in duration. The magnitude of the seismic wave oscillations may vary or remain at a constant amplitude.
Many other types of equipment are used in seismic projects. As noted above, drilling trucks are used to drill holes in the ground at predetermined locations for positioning and detonating explosive charges. Further, vibrator trucks are used to generate the vibratory energy. Recording equipment is used to record the seismic data. xe2x80x9cLine cuttersxe2x80x9d are used to clear trees and other obstacles from the area in which the sources and receivers are to be placed. Transportation in the survey area is provided by trucks, buses, all terrain vehicles, and other types of vehicles. Helicopters are used to ferry people and equipment to the site of the project. In addition, large scale projects may require over one hundred personnel in the field to perform a myriad of tasks such as clearing the line, setting up and dismantling the equipment, locating the sites for placement of the sources and receivers, precisely determining the coordinates of source and receiver points, as well as numerous other tasks. Such personnel require food, water, lodging and other facilities and resources. Project critical vehicles such as vibrators require prompt fueling. Periodically, equipment malfunctions. Trouble shooting equipment including vehicles, testing and repair equipment is provided in the field along with skilled personnel to trouble shoot the malfunctions and effectuate any necessary repairs. A typical project may include over one hundred personnel and several hundred pieces of equipment, many of which are mobile, and vehicles. Accurately tracking and coordinating these resources is vitally important to increase the efficiency of the survey and thus lower the costs. Managing the field resources, however, becomes increasingly problematic as the size of the project area increases. Many projects may require field-based equipment and personnel spread out over several hundred square miles. Other equipment and personnel may be located in various sites, such as the surveying company""s head office, around the globe.
A typical seismic project begins with a request to a seismic company to run a seismic project in a particular area of the world. The request, from the seismic company""s client, initiates a planning phase in which seismic designers, typically geophysicists, design the project gridxe2x80x94made up of source and receiver points. The designed project grid is to be confirmed and modified in the surveying phase of the overall seismic process. The design activity involves reviewing maps of the area to be surveyed and determining where the seismic sources and receivers should be located. Usually, a series of measurements, or xe2x80x9cshot records,xe2x80x9d are performed in each survey and the sources and receivers must be relocated between each shot record.
Source and receiver locations are determined in three dimensions in terms of geodetic latitude, longitude and height. The height dimension is the distance from a source or receiver point to the surface of a reference ellipsoid. Thus, the height is the distance over or above the ellipsoid. The ellipsoid height is the sum of the geoid height and orthometric height (height above sea level). The ellipsoid is an industry standard whose geometric center is ideally at the center of gravity of the Earth, and whose minor axis coincides with the rotation axis of the Earth. The size and shape of the ellipsoid is chosen to best represent the Earth in the mean sense. The WGS84 (World Geodetic System 1984) is one such industry standard. The accuracy specifications for the coordinates of sources and receivers are generally specified in terms of meter or submeter accuracy. The maintenance and assessment of this accuracy is critical to seismic surveys.
Survey designers use digital maps to help them design the survey. These maps indicate the locations of ponds, roads or other obstructions that may interfere with the otherwise desirable location of the seismic equipment. Thus, the quality of the survey design at least partially is a function of the quality of the maps. Poor quality maps (i.e., inaccurate maps or maps which have not been recently updated) detrimentally impact the quality of seismic survey.
In addition to maps, survey designers must also consider local permitting regulations and surface and mineral rights ownership when designing the survey. A client may desire the survey to be performed over a number of parcels of land, each parcel owned by one or more individuals. Determining ownership interests generally requires access to local deed records. Permits must also be obtained to conduct a survey. Permit requirements may vary from locality to locality.
Seismic equipment is transported by helicopter and truck to the field and setup by field crews. A xe2x80x9ccoordinator shackxe2x80x9d is setup in the vicinity of the area to be surveyed. The coordinator shack usually includes communication and computer equipment used by a coordinator to oversee and manage various activities in the field. Such activities include managing the ground equipment, coordinating helicopters, trucks and line personnel to deploy and retrieve equipment.
The locations of the sources and receivers specified by the survey designer are called xe2x80x9cpre-plotxe2x80x9d coordinates. Ideally, field surveyors position the sources and receivers in the field exactly at the pre-plot coordinates. Using the pre-plot coordinates and standard, albeit not highly accurate positioning techniques, the field personnel estimate the location in the field corresponding to the pre-plot coordinate. Then, using sophisticated locating equipment, such as the Global Positioning System (GPS), the field personnel determine how close their initial estimate was to the pre-plot coordinate, and adjust their location to more precisely match the pre-plot coordinates. The GPS currently includes an array of 24 satellites in orbit approximately 22,000 kilometers above the Earth. Ground-based GPS satellite receivers receive and interpret signals from the GPS satellites to determine the location of each receiver depending on the particular GPS technique used. GPS provides accuracy from about 30 meters to less than 1 meter (i.e., submeter accuracy). The field crew uses GPS receivers to try to position the sources and receivers as close to the pre-plot coordinates as possible.
Unfortunately, it is rarely possible to position the source and receiver equipment exactly at the pre-plot coordinates. Ponds, roads, and other obstructions not shown on the maps used by the survey designers may prevent the equipment from being positioned where specified by the survey. Additionally, even though GPS provides accurate positioning data, the actual location of the equipment still may not exactly match the pre-plot coordinates because of inaccuracies in the GPS system and/or lack of skill in the personnel using the GPS system. At times, GPS equipment may malfunction and personnel may make blunders thereby resulting in erroneous coordinates for the source and recorder points.
Before the shot record is taken, the field personnel determine the actual location of the equipment. These GPS-determined coordinates are referred to as xe2x80x9cactuals.xe2x80x9d Any discrepancy between the actual and pre-plot coordinates may impact the interpretation of the resulting seismic data. It is thus important to relay the actual coordinates to the survey design team for evaluation. The actual coordinates are part of what generally is termed the xe2x80x9cquality controlxe2x80x9d (QC) data. The QC data includes the actual coordinates, usually provided in three dimensions, along with standard deviations associated with each coordinate. The standard deviation of a coordinate provides a statistical indication of the level of accuracy of the measured actual coordinate. Sending the QC data to the design team, which may be located in the seismic survey company""s home office half way around the world, usually is accomplished by facsimile transmission of hand-written or typed out notes, and usually occurs between 3 and 7 days after the preplot coordinates have been surveyed and the shot record is taken. The time lag occurs because communication of data from the field to the home office is not efficient. The inefficiency results from the lack of an electronic communications infrastructure between the field and the office environment.
With QC data, the design team compares the actual coordinates to the pre-plot coordinates and determines whether the actuals were within specification. If some of the actual coordinates are out of specification (actual coordinate too far from the preplot coordinate), the designer must decide whether the survey can simply omit the seismic data from that particular design or whether the xe2x80x9cactualxe2x80x9d location be repositioned or shot record rerun. If the survey designer chooses the latter approach (i.e., resurvey the coordinates of the point, and/or reshoot the record), the equipment, which by then may have been moved to another location to perform another shot record, must be brought back and set up again. Considerable and undesirable time and expense is associated with reshooting a record or resurveying a point for which equipment must be brought back and set up again.
While the survey is underway, the client company often wishes to know the status of the survey as well as be provided with assurance that the acquired seismic data is reliable and usable. Accordingly, the client must hire a person referred to as a xe2x80x9cbird dogxe2x80x9d to follow the seismic field crew and verify the accuracy of the survey. Bird dogs are usually highly trained and expensive resources that add to the cost of the seismic survey. Without bird dogs, however, the client has little insight into the activity in the field as it occurs.
A seismic operation can be broken down into five major areas:
(1) Overall Project Management
(2) Mobilization and Demobilization
(3) Surveying
(4) Drilling
(5) Recording
Overall project management includes planning, designing, and quality control. Mobilization and demobilization involves moving equipment to a survey site, setting it up, disassembling it and moving the equipment to the next site. Surveying refers to the use of conventional survey techniques or GPS to the locating and xe2x80x9cstakingxe2x80x9d of the source and receiver points. The surveying of points can be done by a surveyor ahead of the drilling and recording or it can be done in conjunction with these activities. Drilling operations involve drilling holes at the source points in which the explosive charges are placed. When explosives are not used, vibrators are employed at the source points. Finally, recording includes recording the seismic data detected by the receivers. As noted below, significant shortcomings exist with respect to conventional process of performing seismic survey or project in each of the aforementioned five areas.
In the project management area, one of the major shortcomings includes non-existent or inconsistent use of digital maps. Further, poor quality and/or outdated maps contribute to errors in the design of the survey. Field personnel, for example, may update a map, but there may be a considerable time lag before the updates are provided to the experts in the home office.
Further, the inability to accurately track equipment causes inefficiencies in the coordination of mobile units and people. For example, vehicles may be dispatched to one side of a river or canyon to repair equipment that is located on the other side of the obstacle.
Inefficient tracking of mineral rights and land ownership information associated with permitting is another problem in the project management area driving up the cost of the survey. Local municipalities and other regulatory agencies must be researched each time a survey is to be performed in a particular area by a client. If a different client wishes to survey the same area, that client, or its survey company, must undesirably repeat the same research into ownership and permit issues.
Project management in conventional seismic survey operations usually requires highly skilled, and thus expensive, labor in the field rather than in the office environment. Such people are required to oversee the operation in the field to ensure the integrity of the data. In general, the cost associated with placing a person in the field, which includes travel, lodging, food, etc., is higher than if that person was located at his or her home office. If faster and more efficient communication of data between a central office and the field was available, it might be feasible to locate the higher skilled workers in the office environment, rather than in the field. Further, scattering such skilled personnel across the globe at various seismic project sites does not permit the beneficial sharing of information between the various skilled professionals.
Mobilization and demobilization of equipment and personnel has its own set of problems. For instance, conventional seismic operations do not have a highly accurate, efficient mechanism for tracking the location of the equipment including the vehicles to transport the equipment. It thus is difficult to keep track of transportation vehicles, some of which may still be loading equipment from a previous job while other vehicles are deploying equipment to the next job site hundreds of miles away. The inability to accurately and inefficiently track equipment makes inventory control problematic. One piece of equipment may be stolen or misplaced and not noticed as missing for several days. Additionally, conventional mobilization and demobilization systems do not provide a mechanism for accurately monitoring the time field personnel actually spend working, thereby potentially creating inaccuracies in client billing.
Shortcomings in the surveying phase include excessive waste of time and money having to re-stake points when the surveyor or geophysicist reviews the QC data and determines that a particular surveyed point or shot record must be rerun. As noted above, the increased costs includes bringing equipment back to the site of the original shot record, setting up the equipment again, and repositioning the point or rerunning the shot record. This process may cost 2 to 3 times the cost of the initial record.
In addition, typical seismic survey systems force field personnel to repetitively enter and log the same data leading to longer survey times at higher cost to the client. For example, a driller may provide hand-written reports to the drill supervisor who, in turn, corrects and rewrites the report and delivers the corrected report to the project manager. The project manager then manually inputs the corrected report into a computer and then emails the report to the home office. Not only is this a time consuming and expensive process, considerable room for error exists because of the repeated human involvement with the data entry.
Surveying problems also include a lack of xe2x80x9creal-timexe2x80x9d integrity monitoring available to the client. As such, the client generally is not able to monitor the integrity of the survey as it is occurring without incurring the substantial cost of hiring a bird dog in the field. Additionally, surveying suffers from excessively long time periods in the communication loop between field personnel and the geophysicists in the home office.
In the drilling area, there is considerable redundancy involved with recording and logging drill information. As noted above, drillers maintain hand written logs of hole depth, dynamite charge size, hole cutting analysis and the like. This log is physically handed to the drill manager who revises the log and has the log""s information manually inputted into a computer or other communication device for transmission to the head office. This process is slow and error prone. Drilling operations also rely heavily on physically staked points for positioning of source drills and vibrators. The source point is marked by a survey flag which is imprinted with the drill or vibrator location identifier. These flags often are washed away by rain, buried by snow, or destroyed by cattle or field cultivation. Extra time is expended, at increased cost to the client, to relocate the source point, or the hole may be missed altogether (i.e., not drilled).
Finally, the recording activity has its share of shortcomings as well. Geophysicists in the home office and the client generally are not provided with the recorded quality control data fast enough to analyze the data for accuracy while the equipment is still on location. The inability of conventional seismic systems to provide QC data to the client quickly forces the client undesirably to hire expensive bird dogs in the field as noted previously. Also, currently no conventional seismic system has the capability to transmit all the core seismic data back to the office environment for faster processing and delivery to the client as the end product.
Thus, seismic operations require the planning and coordination of numerous different types of activities and hundreds of personnel. Such activities typically are performed at various sites across the globe making coordination at times a monumentally difficult task. It is highly desirable for the overall seismic operation to be as efficient as possible, thereby reducing time and cost. The problems and inefficiencies of conventional seismic operations, some of which are outlined above, have plagued the seismic industry for a long time. A seismic system that mitigates or solves these problems and provides a more efficient process would be highly desirable. To date, substantial room for improvement exists in the seismic field.
The deficiencies of the prior art described above are solved in large part by a real time data gathering, quality control (xe2x80x9cQCxe2x80x9d) and information distribution system, comprising field resources, satellite resources, and office resources that are located at a different site from the field. The field resources include various personnel, portable offices or traitors, equipment, and vehicles located in the general vicinity of the area to be surveyed. The field resources also include mobile and fixed transceivers allowing the field resources to communicate to the office resources via one or more satellites and experts at an information and control center (xe2x80x9cICCxe2x80x9d) communicate back to field entities. The office resources include the ICC, client and consultant facilities, and one or more public and/or private satellite earth station hubs. The seismic system advantageously facilitates real or near real time transmission of assets, data, voice, and text between the field, the ICC, and client and consulting facilities, thereby providing an efficient seismic operation.
In the preferred embodiment of the invention, five sub-processes or modules preferably are integrated together. These sub-processes include project management, mobilization and demobilization, geodetic surveying, drilling, and seismic data recording. The integration is performed in a systems sense such that a new way of performing the seismic business operation is achieved.
The seismic system of the preferred embodiment uses positional data determined by GPS, or an integration of GPS/IMU (Inertial Measuring Unit), to determine in near real-time, whether the determined set of coordinates of a location in the field (the xe2x80x9cactualsxe2x80x9d) is within specification relative to quality control parameters and with respect to a set of pre-plot coordinates. A mobile unit (e.g., vehicle, sled, backpack) determines its coordinates and sends them along with quality control parameters via satellite communications and the Internet to the ICC, where a knowledge base containing facts and expert rules is used to determine if the actuals are sufficiently close to the pre-plot coordinates given the associated quality control parameters. If a mismatch has occurred, a solution is initially and automatically formulated using the knowledge base, and then reviewed and approved by human experts at the control center. A final decision is then transmitted to the mobile unit in the field, via the Internet and satellite communications, before the field crew leaves the site. All of the information and actions are shared with the appropriate personnel within the group carrying out the work, as well as with the client and their quality control subcontractors, using thin-client Java-based technology over the Internet. Accordingly, personnel in the field can reposition the equipment while they are still at the site of the equipment. The integrated seismic information system is extended to apply to seismic data, permitting information, access information, drilling-related information (e.g., log data), etc.
The various characteristics described above, as well as other features, will be readily apparent to those skilled in the art upon reading the following disclosure.